There are many different factors which can limit the durability of articles besides normal wear during use. Color fading, surface abrasion, and soiling, for example, can sufficiently diminish the aesthetics of an article so that it ought to be replaced. Some items such as photographs and works of art cannot be replaced when such damage has been wrought on them. Most organic materials, including dyes and pigment, are susceptible to degradation by light, the ultraviolet region of the electromagnetic spectrum (approximately 290 to 400 nm) being the most damaging radiation. As conventional fluorescent lighting emits some ultraviolet radiation in this region, avoidance of sunlight is not necessarily complete protection from such radiation. In the past, clear films of synthetic polymers containing ultraviolet absorbers have been used to protect certain items, including color photographs, against fading caused by ultraviolet radiation. The addition of such protective coatings, although reasonably effective against fading, have not provided protection against other deleterious effects such as abrasion and soiling. The coatings also must generally be able to provide impact resistance and flexibility, especially on an article such as a painting or color photograph.
U.S. Pat. No. 4,049,861 discloses abrasion resistant coatings based upon the polymerization of epoxy-terminated silanes. A high degree of abrasion resistance is provided by that technology.
U.S. Pat. No. 4,156,046 discloses an abrasion resistant, bloom resistant coating for use on substrates which are susceptible to damage from ultraviolet radiation, abrasion, and/or soiling. The abrasion resistant ultraviolet radiation protective coatings of U.S. Pat. No. 4,156,046 are highly effective, but tend to be subject to surface crazing when contacted with water. It is surprising that such water sensitivity exists in a coating that is resistant even to very strong solvents, and it would be desirable to eliminate the water-sensitivity.